USER MANUAL
SMALL-SIZE INFRARED GAS SENSOR MIPEX-02-3-RX-1.1 G
ESAT.100200.02.02 UM
September 23, 2021
Page 34 of 41
THE SOLE PROPERTY OF SIA MIPEX. ANY REPRODUCTION WITHOUT THE WRITTEN PERMISSION OF SIA MIPEX IS PROHIBITED.
APPENDIX D. SENSOR CONFIGURATION
Appendix D.1. Zeroing and span calibration
Span calibration is necessary during sensor’s initial installation as well as during the period of
preparation for the equipment checking. It is required to perform span calibration at least once in 30
months. Manual zeroing must be performed before span calibration, after prolonged storage without
power supply, after transportation as well as after dust filter is applied. It is also recommended to
perform manual zeroing when status-word “
31
” shows up (see Appendix F, Table 15 and Table 16).
For the list of CGMs necessary for span calibration, see Table 14.
1. Covering sensor diffusion holes increases response time (T90).
2. Before span calibration operation, it is recommended to send command
<INIT> for calibration and zeroing coefficients initialization. Use this
command only when sensor atmosphere is filled with pure air or high purity
nitrogen.
3. While span calibration is being carried out, avoid:
•
excessive pressure on sensor housing,
•
> 98% humidity,
•
pressure of flowing gas less than 99 kPa and more than 103 kPa;
•
temperature changes faster than by 0.6 °C/min,
•
dust ingress (if dust filter is not used),
•
data request rate more than 1 Hz.
4. Recommended gas feeding rate when using gas adapters ESAT.200210.00:
•
100-150 mL/min for one sensor;
•
500-600 mL/min for 50 consecutively connected sensors.
Zeroing and span calibration should be carried out by qualified personnel outside of an
explosive area under normal conditions in the following sequence:
1. Communicate sensor via UART interface (example based on MIPEX-02/03 interface
board ESAT.200200.00 is shown on Fig. 10; gas adapter ESAT.200210.00 is available as
an option).
2. Auto-zeroing procedure of sensor concentration readings starts automatically during
sensor self-diagnostics after power is switched on. Sensor self-diagnostics runs constantly
while power is on. Use the following commands to control the algorithm: <AZERO ON>,
<AZERO OFF> and <AZERO?>. However, if zero shifts anyway, it is recommended to
perform zeroing manually
:
2.1. within 5 minutes after power was supplied start feeding CGM #1 (high purity
nitrogen) into sensor atmosphere;
2.2. one minute after CGM #1 was supplied, send command <ZERO2>; thus, sensor
readings on the concentration will be set to zero;
2.3. stop feeding CGM #1 into sensor atmosphere;